I recall in the Guild newsletter from the late 90’s they mentioned the D-25 was the best seller they ever had. As far as what comes in second is anyone’s guess, I would guess maybe a D-4 because I see them all the time but that doesn’t mean much. IIRC the D-35 was axed off in 86/87’ and I do know the D-40 seemed to have had a slight hiatus in the late 80’s early 90’s at least it’s not in the 1992-1995 price list which would possibly suggest that these models stopped selling as well as they once did or perhaps it was axed to rejuvenate interest in Guild.
"More D25's have been sold than any other Guild":
Ever since I first noticed D4's and D25's shared the same s/n sequence from '94 forward, though, I've wondered if D4 figures were rolled into that D25 total. One would assume Guild took their figures from s/n records, but there's no way to tell D4's from D25's after '94 going only by the s/n. So I wonder if even Guild knew how many of each were sold.
Re D40 waning demand? Think more likely just a part of the model line-up revamp that saw the DV52 evolve from the D50 and the D4 from the D25, although in that case the D25 was retained.
But the D40 was replaced by the D6/DV6 for the flatback 'hog body dreadnought slot, and
they (DV6 and 1-year only DV25 and even DV4, anyway) were dropped when the D40 was brought back with a narrow headstock for the final Westerly years and early first year Corona.